Fibre filling materials are used for filling into articles of bedding, such as pillows, sleeping bags and quilts, to provide a comfortable feeling and insulation.
EP 0 203 469 B1 describes one example of a fibre filling material in the form of refluffable fibre balls that are made from siliconized staple fibres that are entangled. The fibre balls according to that document are commercially available from ADVANSA Polyester GmbH, Hamm, Del. and sold under the trade marks Comforel® T-287, Comforel® supreme and others.
Although the fibre balls described in EP 0 203 469 B1 have excellent properties as a filling material providing an excellent bulkiness, i.e. ability to fill a large volume with a low mass of fibre balls, good softness, and good recovery from compression, it has, in some applications, a touch with a certain feeling of singular structures inside a pillow being filled with the fibre balls. Thus a pillow filled with the fibre balls may have a somewhat “grainy” feeling upon touch. This “grainy” feeling is negative to the soft touch feeling of the object, such as a pillow, into which the filling material is filled.
In applications where a “grainy” feeling is not desired it is often practice to fill the pillow with down or a combination of down and feathers. A filling material containing a combination of down and a substantial amount of feathers, such as 25-75% feathers, has a rather low ability to fill out a pillow, i.e. a poor bulkiness and thereby a “flat” feeling, and also provides an uncomfortable feeling since you can feel the hard central quill shafts of the large amount of feathers through the pillow fabric. A filling material containing mostly down, such as 90% down and only 10% feathers, is on the other hand very expensive and has a too quick recovery after compression. By this is meant that an object, such as a pillow, filled with such an exclusive down material will, after compression, very quickly return to its original size. Thus the pillow filled with mostly down might give a feeling with too quick recovery after compression. Such a “springy” feeling, which may also be felt in the Comforel® T-287 material, is negative to the feeling of conformability to the body by the filling material. By conformability is meant the pressure on a part of a body, such as a head, which is exerted by an object, such as a pillow. A good conformability, which is a desirable characteristic, means that a low pressure is exerted by the pillow on the head of a person lying on the pillow. It is difficult to obtain a combination of feathers and down that provides both a good bulkiness and a high conformability.